Drill

Abstract

Drill for drilling in hard materials, including a drill head having a rotational axis, wherein the drill head includes an apex aligned with the rotational axis and centre point cutting edges radially extending and receding from the apex. A first one of the centre point cutting edges and a second one of the centre point cutting edges have a different radius and/or are receding at least for a part at a different rate. A drill for drilling in hard materials, including a drill head having a rotational axis. The drill head includes a centre point aligned with the rotational axis and main cutting edges radially extending from the centre point, wherein each of the main cutting edges deviates from a radial.

1 - 33 . (canceled) 
     
     
         34 . A drill ( 100 ) for drilling in hard materials, comprising a drill head ( 150 ) having a rotational axis (R), wherein the drill head comprises a centre point ( 180 ) comprising:
 an apex ( 182 ) aligned with the rotational axis;   centre point cutting edges ( 181 ,  181 ′) radially extending and receding from the apex,   main cutting edges ( 160 ,  160 ′) radially extending from the centre point ( 180 ), wherein a first one of the centre point cutting edges and a second one of the centre point cutting edges have a different radius (r1, r2) and/or are receding at least for a part at a different rate;   wherein the centre point comprises an asymmetric cutting edge ( 183 ) arranged between a proximal end ( 172 ′) of one of the main cutting edges ( 160 ,  160 ′) and a distal end of one of the centre point cutting edges ( 181 ′); and   wherein a proximal end ( 172 ) of another one of the main cutting edges ( 160 ,  160 ′) ends at a distal end of another one of the centre point cutting edges ( 181 ).   
     
     
         35 . The drill according to  claim 34 , wherein the centre point cutting edges are angularly evenly distributed around the apex. 
     
     
         36 . The drill according to  claim 34 , wherein the centre point cutting edges deviate and/or curve away from a radial. 
     
     
         37 . The drill according to  claim 36 , wherein the centre point cutting edges are convex centre point cutting edges. 
     
     
         38 . The drill according to  claim 34 , wherein the centre point cutting edges recede from the apex at the same rate. 
     
     
         39 . The drill according to  claim 34 , wherein the part of the first one of the centre point cutting edges and the part of the second one of the centre point cutting edges having a different rate of receding are arranged distal from the apex. 
     
     
         40 . The drill according to  claim 34 , wherein the drill head comprises main cutting edges ( 160 ,  160 ′) radially extending from the centre point. 
     
     
         41 . The drill according to  claim 40 , wherein a proximal end ( 172 ,  172 ′) of each of the main cutting edges ends at a distal end of the centre point cutting edges. 
     
     
         42 . The drill according to  claim 41 , wherein the asymmetric cutting edge is extending in a direction different from the direction of the distal end of the one of the centre point cutting edges. 
     
     
         43 . The drill according to  claim 34 , wherein the drill is a high-speed steel (HSS) drill. 
     
     
         44 . The drill according to  claim 34 , wherein the number of centre point cutting edges is two, three or four. 
     
     
         45 . The drill according to  claim 34 , wherein the number of centre point cutting edges is two and the two centre point cutting edges form an S-shape with the apex as rotational symmetric point. 
     
     
         46 . The drill according to  claim 34 , wherein the drill is combined with any of the features of the embodiments specified in EMBODIMENTS. 
     
     
         47 . The drill ( 100 ) according to  claim 34 , wherein each of the main cutting edges ( 160 ,  160 ′) deviates from a radial (Rad). 
     
     
         48 . The drill ( 100 ) according to  claim 47 , wherein the deviation of one of the main cutting edges ( 160 ,  160 ′) is defined as that there exists a tangent line tangent to a point of the main cutting edge ( 160 ,  160 ′), wherein the tangent line has a non-zero angle with the radial through that point. 
     
     
         49 . The drill ( 100 ) according to  claim 34 , wherein each of the main cutting edges ( 160 ,  160 ′) comprise at least one section that deviates and/or curves away from the radial. 
     
     
         50 . The drill ( 100 ) according to  claim 34 , wherein each of the main cutting edges ( 160 ,  160 ′) comprises a convex edge section ( 165 ,  165 ′). 
     
     
         51 . The drill ( 100 ) according to  claim 50 , wherein the drill head has a drill head ( 150 ) circumference (C) and wherein a distal end ( 166 ,  166 ′) of each of the convex edge sections ends at the drill head circumference. 
     
     
         52 . The drill ( 100 ) according to  claim 34 , wherein the drill ( 100 ) has a drill circumference (C), and comprises at least two guiding lands ( 190 ,  190 ′,  191 ,  191 ′) arranged to the drill circumference and spiraling away from the drill head. 
     
     
         53 . The drill ( 100 ) according to  claim 52 , wherein the at least two guiding lands start at the drill head circumference. 
     
     
         54 . The drill ( 100 ) according to  claim 53 , wherein an end of the respective at least two guiding lands ( 190 ,  190 ′) is adjacent to a respective distal end ( 166 ,  166 ′) of one of the convex edge sections. 
     
     
         55 . The drill ( 100 ) according to  claim 34 , wherein each of the main cutting edges ( 160 ,  160 ′) comprises a concave edge section ( 165 ,  165 ′). 
     
     
         56 . The drill ( 100 ) according to  claim 55 , wherein the concave edge section is arranged proximal relative to the convex edge section ( 165 ,  165 ′). 
     
     
         57 . The drill ( 100 ) according to  claim 34 , wherein the concave edge section ( 165 ) and the convex edge section ( 165 ′) are adjoining. 
     
     
         58 . The drill ( 100 ) according to  claim 55 , wherein a proximal end ( 172 ,  172 ′) of each of the concave edge sections ( 165 ,  165 ′) ends at the centre point ( 180 ). 
     
     
         59 . The drill ( 100 ) according to  claim 34 , wherein the centre point ( 180 ) protrudes from the drill head for centring the drill head ( 150 ) in use. 
     
     
         60 . The drill ( 100 ) according to  claim 34 , wherein the hard material is a metal. 
     
     
         61 . The drill ( 100 ) according to  claim 60 , wherein the metal is a hard metal, such as steel. 
     
     
         62 . The drill ( 100 ) according to  claim 61 , wherein the drill is a highspeed steel (HSS) drill. 
     
     
         63 . The drill ( 100 ) according to  claim 34 , wherein the number of main cutting edges ( 160 ,  160 ′) is two, three or four. 
     
     
         64 . The drill ( 100 ) according to  claim 34 , wherein the main cutting edges ( 160 ,  160 ′) define a cutting plane substantially perpendicular to the rotational axis (R). 
     
     
         65 . The drill ( 100 ) according to  claim 34 , wherein the main cutting edges ( 160 ,  160 ′) are angularly evenly distributed around the centre point ( 180 ).